Neuroprosthetics constitutes an important field for the application of active implants. In this sector, CorTec has developed a closed-loop system for measuring and stimulating brain activity for long-term use. “The driving premise behind our work is the realization that these kinds of therapies need to be personalized,” said Dr. Martin Schüttler, founder and CEO of CorTec. The Brain Interchange concept consists of three components: Electrodes for recording and stimulating the nervous system, a telemetric unit for optical communication with both the implant and the computer unit that evaluates the brain signals in real time in order to determine the level of stimulation that the patient requires at that point in time. CorTec manufactures the electrodes itself. They consist of five layers which are created using ultrashort pulse lasers and microfabrication methods. Consequently, the electrodes can be produced in any geometric shape (three dimensional or in a cuff design), with high contact density and for a wide variety of applications. CorTec thus manufactures both components and complete active systems.

Biodegradable materials for reabsorbable implants
Many implants need to have a lifespan that is as long as possible, but for others, it is important that they do not remain in the body long-term. At the IFAM (Fraunhofer Institute for Manufacturing Technology and Advanced Materials) in Dresden (Germany), a biodegradable magnesium implant with a fibrous structure has been developed as a solution for treating major bone defects. This serves as a guiding structure for the bone while it is growing, with this growth being particularly stimulated by the well-suited biomechanical properties of the implant. This structure also stimulates blood vessel growth simultaneously. The implant degrades as the healing process progresses. Up until now, major bone damage has mainly been treated by grafts taken from the patient’s own bones. This is, evidently, only possible to a limited extent. In addition, harvesting the graft, which generally comes from the iliac crest, harbors additional risks for the patients. Synthetic bone replacements represent an alternative here, but often these can only withstand little mechanical stress and are unsuitable as a result of the disruptions they cause in imaging in the long-term. Biodegradable materials therefore represent the ideal solution; they are used to create implants that disappear once the healing process has been successfully completed, such as the innovative magnesium implant from the Fraunhofer IFAM in Dresden, which was discussed at the COMPAMED Spring Convention. The starting point for technological development is the manufacturing of short magnesium fibers via extraction from the melt. These fibers are then homogeneously deposited and bonded to each other and densified via heat treatment. Implants manufactured this way have excellent mechanical properties and, most importantly, stellar corrosion properties, which are particularly well suited to the physiological tasks required of them. In the animal model, slow corrosion was thus first measured after 12 weeks, and after 24 weeks the majority of the metallic component had disappeared. Osteosynthesis and cardiovascular stents are considered the most significant commercial applications for this technology.

Association Viewpoints Homepage